Field of the Invention
The present invention relates to a timbre control apparatus, for an electronic musical instrument, that controls the timbre for a musical tone to be produced.
Current tone generators for electronic musical instruments have multiple oscillators, and drive the oscillators, which are paired as needed, to simultaneously produce a plurality of musical tones.
A timbre for a musical tone is generated by providing the oscillators with predetermined timbre data. Various forms of such timbre data are held by an electronic musical instrument.
Currently, the production of musical tones having many timbres is required of electronic musical instruments, and the volume of timbre data stored in an electronic musical instrument is accordingly large. A timbre control apparatus is desired, therefore, that can efficiently store timbre data and that can perform tone production within a short period of time following the issue of a tone-ON command.
Description of the Related Art
In general, conventional electronic musical instruments hold timbre data that correspond to the musical tones for every tone range. Thus, for example, when a key is depressed on an electronic musical instrument that holds timbre data for piano timbre production for every octave, the electronic musical instrument, in response, reads and employs timbre data for the octave to which the depressed key belongs to produce a musical tone having that timbre.
Electronic musical instruments, such as synthesizers, are generally so designed that a user can change timbres selectively. To change a timbre with such an electronic musical instrument, for example, envelope information about an envelope that is included in timbre data should be altered.
Therefore, to change the full range of timbres by shortening the total attenuation time of a piano tone, for example, the envelope information in the timbre data that correspond to the respective octaves has to be altered for all the octaves.
As a result, timbre alteration cannot be quickly performed by the above described electronic musical instrument, and its manipulation of timbres is poor.
In another known means for changing the full range of timbres, the timbre data for every tone range is calculated by means of an arithmetic function. With this method, the full range of timbres can be altered by changing a value that is employed for the arithmetic function.
Calculation time, however, is excessive because when a function that includes multiplication, for example, is employed to calculate data for each tone generation, the time lapse between the issue of a tone production instruction and tone production is extended. Further, since various functions have to be employed to obtain a desired timbre, the total volume of timbre data is increased.